Dental angle handpiece for root canal treatment

ABSTRACT

DENTAL APPARATUS INCLUDES A HEAD PART AND COMPRISES DRIVE MECHANISM FOR IMPARTING OSCILLATING MOVEMENT TO A CANAL INSTRUMENT OR TOOL. THE DRIVE MECHANISM INCLUDES A WOBBLE PLATE ROTATABLE BY THE DRIVE SHAFT OF AN ANGLE HANDPIECE AND IS ADAPTED TO IMPART AXIAL DISPLACEMENT ALTERNATELY TO TWO PUSH RODS, THE LATTER ENGAGING TRANSVERSE SURFACES OF A DRIVE SLEEVE IN SUCH A MANNER THAT THE CONTINUOUS ROTARY MOTION OF THE DRIVE SHAFT IS CONVERTED TO IMPART OSCILLATING MOVEMENT TO THE DRIVE SLEEVE.

H. LOGE Jan. 19, 1971' DENTAL ANGLE HANDPIECE FOR ROOT CANAL TREATMENT Filed Nov. 6, 1968 HG. l

United States Patent DENTAL ANGLE HANDPIECE FOR ROOT CANAL TREATMENT Hans Loge, Biberach an der Riss, Germany, assignor t0 Kaltenbach & Voigt, Biberach an der Riss, Germany Filed Nov. 6, 1968, Ser. No. 773,707 Claims priority, application Germany, Nov. 8, 1967, 1,566,243 Int. Cl. A61c 3/08 US. Cl. 3257 5 Claims ABSTRACT OF THE DISCLOSURE Dental apparatus includes a head part and comprises drive mechanism for imparting oscillating movement to a canal instrument or tool. The drive mechanism includes a wobble plate rotatable by the drive shaft of an angle handpiece and is adapted to impart axial displacement alternately to two push rods, the latter engaging transverse surfaces of a drive sleeve in such a manner that the continuous rotary motion of the drive shaft is converted to impart oscillating movement to the drive sleeve.

This invention relates to a dental angle handpiece for the treatment of tooth root canals.

Though this operation has long been carried out manually, using a root canal instrument such as a flexible canal file, it is nowadays frequently performed mechanically with the aid of an angle handpiece in conjunction with a head part constructed specially for this purpose. In known devices of this kind the continuous rotation of the driving shaft is converted into oscillating movement imparted to the tool holder through the engagement of an eccentrically mounted pivot on a drive-shaft cam cooperating with a recess in the toolholder.

Such constructions have the disadvantage of being extremely difficult to reassemble after sterilization, since the moving parts are displaced and it is extremely difficult to bring the dismantled components properly into gear again. Known designs of eccentric gearing have, moreover, the disadvantage that they become jammed and thus consequently immobilize the instrument. Finally, the known designs are exposed to considerable wear and tear, since the edges of the groove in the toolholder act as scraper edges on the eccentric pivots.

The fundamental purpose of the invention is to simplify the design of the mechanism situated in the head part of the angle handpiece which converts the rapid rotation of the drive into oscillating movement required for the canal instrument, so as to facilitate simple dismantling and reassembly. Furthermore the invention pursues the purpose of obtaining a silent and abrasion-free operation.

Accordingly, the invention provides a head part for a dental angle handpiece said head part comprising a drive sleeve for the reception of a dental canal instrument, and drive mechanism in said head part operable by a drive shaft of a dental angle handpiece for imparting oscillating movement to said drive sleeve, said drive mechanism comprising a wobble plate, a rotary shaft for rotating said wobble plate, and two push rods mounted for axial displacement in said head part, said push rods cooperating with said wobble plate at one end and operatively engaging said drive sleeve at the opposite end for converting a continuous rotary movement of said rotary shaft and the associated wobble plate to impart oscillating movement to said drive sleeve.

For a better understanding of the invention, an embodiment thereof will now be described, by way of example with reference to the accompanying drawing, in which:

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FIG. 1 is a side view of a head with a canal instrument inserted therein, and part of an angle handpiece, and

FIG. 2 is a sectional view taken through the head and the angle handpiece along the line II of FIG. 1.

In FIG. 1, the reference 1 designates the lower part of an angle handpiece, on which a head 3 is fitted. A head sleeve 2 having locking holes 2a adapted to be engaged in known manner by a locking pin (not shown), is arranged to prevent inadvertent displacement of the head 3 from the lower part 1 of the angle handpiece. A canal instrument 4 is inserted in the head.

FIG. 2 shows details of the aforementioned parts. A shaft, part of which is shown at 5, is mounted in the lower part 1 of the angle handpiece for rotation by a suitable drive e.g. an articulated sliding joint connection (not shown). A gearwheel 6 is mounted on the shaft 5. The lower part 1 of the angle handpiece terminates at the head side in a knee 1a. An intermediate bearing element 8 is screwed at 1b into this knee 1a. A shaft 9 is arranged for rotation in this intermediate bearing element in two bearings of which one is shown in cross-section at 10. At the drive input end, the shaft 9 carries a gearwheel 7 which meshes with the gearwheel 6 in such a manner that driving power can be transmitted at an angle. At the drive output end, the shaft 9 carries a wobble plate 11 whose end face 11a inclined at a specific angle relatively to the longitudinal axis carries out a rotating tumbling movement when the driving shaft rotates. The angle of the inclination enclosed by the end face and the longitudinal axis is conveniently between 50 and 60.

It is known per se to use such wobble plates as control means. In the present case, the wobble plate 11 cooperates with two push rods 12 and 13 which are arranged to be axially displaceable in the head part 14. The push rods have conically tapered ends and the ends of such rods remote from the wobble plate 11 bear against the surfaces 16a of a driving sleeve 16 mounted in the head between two bearings. The canal instrument 4 has a fixing shank shown at 15 in FIG. 2.

The mechanism situated in the head part 14 operates as follows: as the driving shaft 5 rotates, the gearwheel 6 transmits its rotational movement by way of the gear wheel 7 to the shaft 9 mounted in the intermediate bearing element 8.

With it there also rotates the wobble plate 11 which owing to the circulating wobbling movement of the end face 11a, axially displaces the push rods 12 and 13 alternately. E.g. the push rod 13 pushes against the left-hand part of the surface 16a of the bottom of the groove in the driving sleeve and rotates the driving sleeve towards the right through an angle of from about 60 to The right-hand part of the surface 16a at the same time presses the push row 12 back. The push rod can slide back since the space for this has been freed by rotation of the inclined end face 11a. This operation is repeated as long as the rotation of the shaft 9 is maintained. The driving sleeve 16 oscillating thus also imparts a similar movement to the canal instrument 4.

The advantage of this arrangement consists on the one hand in that the head part is very simple from the constructional point of view and on the other hand in the fact that the wobble plate always has to move equal masses in the form of the two push rods i.e. a desirable mass equilibrium is obtained to a certain extent. This means that the angle handpiece with the head part attached lies very steadily in the dentists hand, which is also to the patients adavntage.

I claim:

1. A dental angle handpiece including a head comprising a drive sleeve pivotably supported in said head, said drive sleeve being adapted for securely receiving a dental canal instrument, and driving means supported in said head for imparting oscillating movement to said drive sleeve, said driving means comprising a wobble plate, a rotatably supported shaft including opposite end portions, said wobble plate being connected to one end portion of said shaft to rotate therewith, means for rotating the other end portion of said shaft, said wobble plate including an inclined face, and a pair of axially displaceable spaced push rods, each including opposite end portions, one end portion of each of said push rods being slidingly engageable with said inclined face of said wobble plate, said drive sleeve including abutment means, the other end portion of each of said push rods being alternately engageable with said abutment means of said drive sleeve to oscillate said drive sleeve about the pivotal axis thereof.

2. A dental angle handpiece as claimed in claim 1 wherein said drive sleeve is cylindrical, said abutment means including a pair of oppositely spaced laterally extending surfaces constituting portions of a recess provided in said cylindrical drive sleeve.

3. A dental angle handpiece as claimed in claim 1 wherein said inclined face of said wobble plate is inclined 4 at an angle between 50 and 60 relative to said shaft connected to said wobble plate.

4. A dental angle handpiece as claimed in claim 1, wherein said other end portion of said shaft includes a gear, said gear including a plurality of teeth in circumferential array, and said means for rotating said other end portion of said shaft includes a rotatable gear including a plurality of teeth in meshing relation with the gear of said shaft, whereby a continuous rotary movement is imparted to said shaft, and which continuous rotary movement is converted into an oscillatory movement imparted to said drive sleeve.

5. A dental angle handpiece as claimed in claim 4 wherein said rotatable gear is inclined relative to the gear of said shaft.

References Cited UNITED STATES PATENTS 1,711,846 5/1929 Heilborn 3257X ROBERT PESHOCK, Primary Examiner 

